Application of a lithium secondary battery is rapidly expanded not only as portable power sources for mobile phones, notebook computers, digital cameras, and camcorders, etc., but also as medium and large power sources for power tools, electric bicycles, hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), etc. As these application fields are expanded and the demand is increased, an external shape and a size of the battery are variously changed, and performance and stability are required to be higher than those required in conventional small batteries. In order to meet such a demand, performance of the battery should be stably implemented under a condition that a large current flows.
The lithium secondary battery is produced by using materials capable of inserting and removing lithium ions as an anode and a cathode, installing a porous separator between the two electrodes, and injecting a liquid electrolyte. Electricity is generated or consumed by an oxidation-reduction reaction according to the insertion and removal of the lithium ions in the anode and the cathode.
Various reviews on non-aqueous solvents or additives have been studied as components provided in an electrolyte in order to improve battery characteristics such as output characteristics, cycle characteristics, and storage characteristics, etc., of the lithium ion battery. Further, even when a specific compound is added to the electrolyte as an additive in order to improve the battery performance, performance of some items of most battery performance may be expected to be improved, but the performance of other items is rather reduced.